Covalent functionalization of solid cellulose by divergent synthesis of chemically active dendrons
Covalent functionalization of solid cellulose by divergent synthesis of chemically active dendrons
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DOI：
10.1002/pola.29171
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发表时间：
2018-09-15
影响因子：
--
通讯作者：
Amir, Elizabeth
中科院分区：
文献类型：
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作者：
Anavi, Daniel;Popowski, Yanay;Amir, Elizabeth
介绍了用具有化学反应活性的树枝状基元共价修饰固体纤维素作为纤维素接枝功能材料的平台。第一代树枝化基元的表面官能化是通过在温和条件和短反应时间下使用基于2，2-双（羟甲基）丙酸（bis-MPA）的双官能分子进行酯化来实现的。活化的纤维素表面显示疏水特性，并含有两个反应性烯烃端基每个接枝，这是用于共价结合到活性剂，如通过选择性官能化的改性纤维素与荧光染料通过荧光染色证明。纤维素表面上的活性端基的数量乘以发散固态合成的第二代和第三代树突具有四个和八个反应位点，每个树突，分别。通过一系列硫醇-烯/酯化反应，在短短几个小时内组装出树枝状分子。精确控制纤维素表面上的结合位点的数量的能力允许精细调节表面性质，如疏水性小分子与树枝化纤维素的附着所示。第一、第二和第三代树枝化基元允许制备具有增加的疏水性的表面;用小的全氟烷基分子官能化的第二和第三代树枝化基元显示超疏水性质。(C)2018 Wiley Periodicals，Inc.
Covalent surface modification of solid cellulose with well-defined and chemically reactive dendrons is introduced as a platform for cellulose grafting with functional materials. Surface functionalization with a first generation dendron is achieved by esterification employing bifunctional molecules based on 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) under mild conditions and short reaction times. The activated cellulose surface displays hydrophobic properties and contains two reactive alkene end-groups per graft, which are used for covalent binding to active agents, as demonstrated by selective functionalization of the modified cellulose with fluorescent dye via photopatterning. The number of active end-groups on the surface of cellulose is multiplied by divergent solid-state synthesis of second and third generation dendrons having four and eight reactive sites per dendron, respectively. The dendrons are assembled in only few hours by a sequence of thiol-ene/esterification reactions. The ability to accurately control the number of binding sites on the surface of cellulose allows fine tuning of the surface properties, as shown by the attachment of hydrophobic small molecules to the dendronized cellulose. The first, second and third generation dendrons allow preparing surfaces with increasing hydrophobicities; second and third generation dendrons functionalized with small perfluoroalkyl molecule display superhydrophobic properties. (C) 2018 Wiley Periodicals, Inc.